Pressure package system

ABSTRACT

A pressure package system for providing a working pressure on a fluid included in a pressure package, the system being provided with a pressure package in which a product chamber is included for holding the fluid and in which a working pressure chamber is included for keeping a propellant at the working pressure, the system being further provided with a pressure controller and a high-pressure chamber connected with the pressure controller for keeping the propellant in supply at a relatively high pressure, the pressure package system being further provided with a wall which is of elastic and/or flexible design, a first side of the wall bounding the working pressure chamber at least partly and a second side of the wall, facing away from the working pressure chamber, bounding the product chamber at least partly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the national stage of international application no.PCT/IB2004/000162, filed 20 Jan. 2004, and claims priority to Dutchapplication no. NL1022456, filed 21 Jan. 2003. This application is alsorelated to international application no. PCT/IB2004/000160, filed 20Jan. 2004. Each of these applications is incorporated by referenceherein.

TECHNICAL FIELD

This application relates to a pressure package system for applying aworking pressure to a fluid included in a pressure package.

BACKGROUND

The invention relates to a pressure package system for providing aworking pressure on a fluid included in a pressure package, the systembeing provided with a pressure package in which a product chamber isincluded for holding the fluid and in which a working pressure chamberis included for keeping a propellant at the working pressure, the systembeing further provided with a pressure controller and a high-pressurechamber connected with the pressure controller for keeping thepropellant in supply at a relatively high pressure, the system beingfurther arranged to supply the propellant from the high-pressure chamberto the working pressure chamber with the aid of the pressure controlleron the basis of a reference pressure, for maintaining the workingpressure in the working pressure chamber.

Such a pressure package system is known from WO 99/62791. In this knownsystem, the pressure controller with the high-pressure chamber connectedthereto, is included in the pressure package as a pressure controldevice. The pressure package is of elongate and substantiallycylindrical design. The pressure control device is so designed as toalign with the inner walls of the cylinder jacket. The pressure controldevice can move in an axial direction of the pressure package under theinfluence of pressure differences in the pressure package. In this knownsystem, the pressure control device constitutes the separation betweenthe product chamber and the working pressure chamber. It will be clearthat a “high-pressure chamber connected with the pressure controller” isunderstood to mean a high-pressure chamber and a pressure controllerbetween which a fluid communication can be effected for the purpose ofcontrolling the working pressure with the aid of a propellant from thehigh-pressure chamber.

The reference pressure is slightly lower than a predetermined workingpressure which it is desired to apply to the fluid operatively includedin the product chamber. The working pressure is a pressure to be keptsubstantially constant. The known system works as follows. When thepressure in the product chamber starts to decrease to a new pressure inthe product chamber because, for instance, a user has allowed fluid toflow from the pressure package, the pressure control device moves, as aresult of the pressure difference between the working pressure chamberand the product chamber, in the direction of the product chamber. Thevolume of the working pressure chamber thereby increases and, as aresult, the pressure in the working pressure chamber decreases. In thatcase, the reference pressure is higher than the new pressure in theworking pressure chamber. The pressure control device is arranged inthat case to allow propellant to flow from the high-pressure chamber tothe working pressure chamber. As a result, the pressure in the workingpressure chamber increases until in the working pressure chamber thepressure has become slightly higher than the reference pressure. Theworking pressure is then higher than the pressure in the product chamberagain, and under the influence of the pressure difference between theproduct chamber and the working pressure chamber the pressure controldevice moves a little further in the direction of the product chamber.Since the volume of the product chamber thereby decreases slightly, thepressure in the product chamber will increase slightly. With thedecrease of the volume of the product chamber, the volume of the workingpressure chamber increases again. The pressure in the working pressurechamber is then a bit lower again than the reference pressure, and thepressure control device will again allow a bit of propellant to flow tothe working pressure chamber, etc.

When the pressure prevailing in the working pressure chamber is slightlyhigher than the reference pressure, the supply of propellant from thehigh-pressure chamber to the working pressure chamber will block. Thepressure control device will then assume such a position that thepressure in the working pressure chamber and the pressure in the productchamber are equal to each other. In that case, this pressure will be theintended working pressure which is slightly higher than the referencepressure.

In the known system, for separating the working pressure chamber and theproduct chamber, the pressure control device is provided with sealingswhich abut the inner wall of the cylindrically designed pressure packagein such in way as to provide a gas-tight closure between the workingpressure chamber and the product chamber. Further, the sealings abut theinner wall in such a way that the pressure control device is stillmovable in the axial direction of the pressure package under theinfluence of a pressure difference between the working pressure chamberand the product chamber. As a consequence, in order for the pressurecontrol device to move, much friction is to be overcome. As aconsequence of this, in turn, the pressure difference between theworking pressure chamber and the product chamber must be relativelygreat before this difference is annulled.

SUMMARY

The object of the invention is to provide a system with which theabove-mentioned drawback of the known system is met. This object hasbeen achieved with the system according to the invention, which ischaracterized in that the pressure package system is further providedwith a wall which is of elastic and/or flexible design, a first side ofthe wall bounding the working pressure chamber at least partly and asecond side of the wall, facing away from the working pressure chamber,bounding the product chamber at least partly. When the pressure in theproduct chamber has decreased because a user has allowed fluid to flowout of the pressure package, then, when an elastic wall is used, theelastic wall stretches in the direction of the product chamber. In thecase of a flexible wall, the flexible wall moves in the direction of theproduct chamber when the pressure in the product chamber has decreased.It is also possible for the flexible wall to unfold, or, conversely, tofold up, under the influence of a pressure difference between theproduct chamber and the working pressure chamber, for reducing thevolume of the product chamber. An advantage of the pressure packagesystem according to the invention is that the elastic or flexible wallcan move within the pressure package virtually without friction.Further, an elastic or flexible wall can be made of relatively lightdesign, resulting in a quick reaction of the wall to pressuredifferences between the product chamber and the working pressurechamber. This is an advantage over the known pressure control device,which is of relatively heavy design and due to inertia is slow to getmoving.

Preferably, the pressure package comprises a provision for opening thepressure package for the purpose of allowing the fluid operativelycontained in the product chamber to flow out of it. This enhances theease with which a user can allow the fluid to flow from the package.

In a particular embodiment, the first side of the wall bounds theworking pressure chamber virtually completely. Further, in that case,preferably, the product chamber is furthermore partly bounded by thepressure package. This also enables a very compact design of thepressure package.

Thus, the working pressure chamber can comprise an inner space of aballoon in which, in use, the propellant can be received. When morepropellant is admitted to the balloon, the balloon will increase involume. The wall whose first side bounds the working pressure chamber ismanufactured from elastic material in this case.

It is also possible, however, that the working pressure chambercomprises an inner space of a bellows in which, in use, the propellantcan be received. The material from which the bellows is manufactured, atleast in part, is of flexible design. In other words, in this case, theworking pressure chamber is at least partly bounded by a flexible wall.

In an alternative embodiment, the second side of the wall substantiallycompletely bounds the product chamber. Further, in that case,preferably, the working pressure chamber is furthermore partly boundedby inner walls of the pressure package. This also enables a very compactpressure package design.

Thus, the product chamber can comprise a bag with an opening, theopening linking up with the provision provided in the pressure packagefor opening the pressure package. The wall whose second side bounds theproduct chamber is manufactured from a flexible material in this case.Preferably, the bag is manufactured from a material having a lowcoefficient of friction.

In this alternative embodiment, however, it is also possible that theproduct chamber comprises a bellows with an opening, the opening linkingup with the provision provided in the pressure package for opening thepressure package. In use, the fluid can be contained in the bellows. Thematerial of which the bellows is at least partly manufactured is offlexible design in this case too. In other words, in this case, theproduct chamber is at least partly bounded by a flexible wall.

In a substantially ready-to-use pressure package system according to theinvention, a propellant is included in the high-pressure chamber.Preferably, the propellant comprises a relatively inert gas. Thisenhances safety. Moreover, a relatively inert gas isenvironment-friendly. As a consequence, less stringent requirements needto be imposed on the pressure package system than is the case withpressure package systems that are provided with a less safe or harmfulpropellant. Although the gas does not come into contact with the fluidoperatively contained in the product chamber, it is a reassuring ideafor many users, especially when the fluid involves a food product, thatno harmful effects can occur upon any contact between the propellant andthe fluid. In an advantageous embodiment, the relatively inert gascomprises a gas from the group consisting of nitrogen and carbondioxide. The reason is that these gases are abundant and cheap.

Furthermore, in a particular embodiment, the system is made of two-partdesign, with a first part comprising the pressure package and a secondpart comprising the pressure controller with the high-pressure chamber.This enables a well-organized design. By making the pressure package oftwo-part design in the manner indicated, the manufacture of the systemis simplified. Incidentally, it is possible for the parts to beintegrally connected with each other. This provides the advantage that asystem is involved that does not include any loose parts.

In an alternative embodiment, however, the parts can be designed asloose items and be connectable with each other for use. Optionally, theparts are detachably connectable with each other. This provides theadvantage that a pressure controller can be used, for instance, forvarious different pressure packages in succession.

Furthermore, preferably, the pressure package is manufacturedsubstantially from a plastic material. This renders the pressure packagelighter compared with a metal pressure package. Moreover, a pressurepackage manufactured from a plastic material can be cheaper than apressure package manufactured from metal.

DESCRIPTION OF DRAWINGS

The invention will presently be elucidated with reference to a drawing.In the drawing:

FIG. 1 schematically shows a cross section of a first embodiment of apressure package system according to the invention;

FIG. 2 schematically shows a cross section of a second embodiment of apressure package system according to the invention;

FIG. 3 schematically shows a cross section of a third embodiment of apressure package system according to the invention;

FIG. 4 schematically shows a cross section of a fourth embodiment of apressure package system according to the invention.

Equal reference numerals denote equal parts in the drawing.

DETAILED DESCRIPTION

FIG. 1 shows a pressure package system 1 for providing a workingpressure on a fluid (not shown) contained in a pressure package 2.System 1 is provided with the pressure package 2 in which a productchamber 3 is included for holding the fluid (not shown) and in which aworking pressure chamber 4 is included for keeping a propellant (notshown) at the working pressure. The system is further provided with apressure controller 5 and a high-pressure chamber 6, connected with thepressure controller 5, for keeping the propellant (not shown) in supplyat a relatively high pressure. In other words, between the high-pressurechamber and the pressure controller, a fluid communication can beestablished for controlling the working pressure with the aid ofpropellant from the high-pressure chamber. The system 1 is arranged foradding, on the basis of a reference pressure, the propellant (not shown)from the high-pressure chamber 6 to the working pressure chamber 4 withthe aid of the pressure controller 5, for preserving the workingpressure that is to be substantially constant in the working pressurechamber 4. The reference pressure can be obtained, for instance, by agas confined in the reference pressure chamber 16. Such a pressurecontroller 5 is known per se, for instance from WO 99/62791. Theoperation of such a pressure controller 5 as shown in FIGS. 1 to 4 willbe further discussed when the operation of the system is discussed.

The pressure package system is further provided with a wall 7 which inthis example is included in the pressure package. The wall 7 shown inFIG. 1 is of elastic design. A first side 8 of the wall 7 bounds theworking pressure chamber 4 substantially completely. A second side 9 ofthe wall 7, facing away from the working pressure chamber 4, bounds theproduct chamber 3 at least partly. The product chamber 3 is furthermorepartly bounded by the pressure package 2. In the exemplary embodimentshown in FIG. 1, an inner space of the working pressure chamber 4comprises a balloon B in which, in use, propellant (not shown) can bereceived. The pressure package 1 further comprises a provision foropening the pressure package 1 for the purpose of allowing the fluid(not shown) operatively contained in the product chamber 3 to flow outof the product chamber 3. In the exemplary embodiment shown in FIG. 1,the pressure package is substantially cylinder-shaped. The pressurepackage is provided with a first end 11 and a second end 12. Adjacentthe first end, the pressure package is provided with an inlet opening 13for the propellant (not shown). The provision 10 for opening thepressure package is situated adjacent the second end 12. The balloon Bis of such design that the balloon B, when being filled with thepropellant, stretches substantially in an axial direction (see arrow A)of the pressure package 1. In the exemplary embodiment shown, theballoon B is tensioned over an air distributor 14. After the filling ofthe balloon B with propellant, the balloon will stretch and assume ashape such as it is shown by the balloon B′ represented in broken lines.It is possible here that parts of the balloon touch the inner wall 15 ofthe pressure package. It is also possible, however, that the balloon B,the air distributor, and the pressure package 2 are so dimensioned withrespect to each other that when the balloon B is being filled, thesecond side 9 of the elastic wall 7 does not touch an inner wall 15 ofthe pressure package 2. In the latter case, there is no frictioninvolved between the second side 9 of the wall 7 and the inner wall 15of the pressure package 2.

The pressure package system 1 shown in FIG. 1 works as follows. In use,the fluid is contained in product space 3. In the high-pressure chamber6, the propellant is held in supply at a relatively high pressure. Thepressure controller 5 shown in FIG. 1 controls the preservation of theworking pressure in the working pressure chamber 4 on the basis of thereference pressure. The pressure controller 5 shown is described atlength in WO 99/62791. Therefore, the operation of the pressurecontroller 5 will be described only briefly. The pressure controller 5is provided with a reference pressure chamber 16. Pressure controller 5is further provided with a closing member 17, designed as a plunger inthis example, movable relative to the reference pressure chamber 16. Theplunger 17 is provided with a sealing ring 18 for preserving a gas (notshown) received in the reference pressure chamber 16 with the referencepressure. The pressure controller 5 is further provided with acylinder-shaped cap 19 which, together with the plunger 17, encloses thereference pressure chamber 16. The cap 19 is provided with athrough-going recess 20 for effecting a gas communication between inletopening 13 of the working pressure chamber and a space 21 which isprovided between the plunger 17 and a closure 22 closing off the cap 19.For effecting the gas communication between the through-going recess 20and the working pressure chamber, a part of the pressure controller 5 isincluded in a cylinder 42 which at one end connects to the inlet opening13 of the working pressure chamber 4 and at another end is closed off bythe pressure controller 5. The through-going recess 20 terminates on oneside in the cylinder 42 and on the other side in the space 21. Closure22 is furthermore provided with a passage 23 in which a stem 24 of theplunger 17 is received with a close fit. Stem 24 is provided with anannular recess 25 to enable the effectuation of a gas communicationbetween the high-pressure chamber 6 and the space 21. The stem 24 of theplunger 17 can move in the passage 23 in the direction of arrow P, suchthat the gas communication between the space 21 and the high-pressurechamber 6 is established. In the situation that is shown in FIG. 1, thegas communication has been established. In this situation, a sealingring 26 included in the passage 23 extends in the annular recess 25 andclears the passage for effectuation of the gas communication. When, fromthe position of the stem 24 shown in FIG. 1, the stem moves further ineither the direction of arrow A or the direction of arrow P, the partsof the cylinder jacket of the stem that are free of the annular recesspress against the sealing ring 26 and hence press the passage 23 shut;the gas communication is blocked and hence broken. The plunger 17 cantherefore be moved from the situation shown in FIG. 1, in the directionof arrow A, such that the gas communication between the space 21 and thehigh-pressure chamber 6 is closed. The effectuation of the gascommunication between the space 21 and the high-pressure chamber 6 isdetermined by the position of the annular recess 25 relative to theclosure 22. The sealing ring arranged in the passage 23 makes acontribution to the closure of the gas communication between the space21 and the high-pressure chamber 6. Such a pressure controller issuitable in particular to keep the working pressure substantiallyconstant. FIG. 1 of WO 99/62791 and the description associated with FIG.1 therein indicate in more detail how the pressure controller 5 can bedesigned and work.

In use, the reference pressure in the reference pressure chamber 16 willbe slightly lower than the working pressure in the working pressurechamber 4. This means that when the product chamber 3 is closed, theworking pressure is exerted on the fluid contained in the productchamber 3. When the pressure package is opened and the fluid is allowedto flow out of the product chamber 3, the pressure in the productchamber 3 decreases. The working pressure still prevailing in theworking pressure chamber 4 is then higher than the pressure in theproduct chamber. The balloon B then stretches in the direction of arrowA. The balloon will then take the shape of balloon B′. The volume of theworking pressure chamber 4 is thereby enlarged and therefore thepressure in the working pressure chamber 4 will decrease. The space 21is in a gas communication with the working pressure chamber 4 by way ofthe through-going recess 20. Accordingly, when the pressure in theworking pressure chamber 4 decreases, the pressure in the space 21 willalso decrease. As a result of a lowered pressure in space 21, theplunger 17 moves in the direction of arrow P, at least when thereference pressure in the reference pressure chamber 16 is higher thanthe pressure in the space 21. It should be noted that a high pressure ofthe gas in the high-pressure chamber 6 as exerted on a subsurface 27will hardly make a contribution to the position of the plunger, sincethis subsurface 27 is very small. As mentioned, when plunger 17 with thestem 24 moves in the direction of arrow P, a gas communication betweenthe space 21 and the high-pressure chamber 6 is effected in the passage23 via the annular recess 25. The propellant operatively contained inthe high-pressure chamber will flow via this gas communication to thespace 21. Via the through-going recess 20 provided in the cap 19, thepropellant will flow via inlet opening 13 to the working pressurechamber 4. As a result, the pressure in the working pressure chamber 4increases and the working pressure chamber 4, that is, the balloon B,will stretch further in axial direction (arrow A) of the cylinder-shapedpressure package. When in the working pressure chamber the workingpressure is slightly higher again than the reference pressure in thereference pressure chamber, the plunger 17 will move in the direction ofarrow A. The gas communication between the space 21 and thehigh-pressure chamber 6 is thereby closed off by the contact between thesealing ring 26 and the stem 24. When the pressure package after beingopened is closed again, the working pressure will also be applied to thefluid contained in the product chamber 3.

FIG. 2 shows a schematic cross section of a second embodiment accordingto the invention. In this embodiment, the working pressure chamber 4comprises an inner space of a bellows Bg in which, in use, thepropellant can be received. The pressure package system 1 is providedwith a wall 7 which is included in the pressure package 2 and in thiscase is of flexible design. In the pressure package 2, in this case, awall 7 is included which is of flexible design. The first side 8 of thewall 7 bounds the working pressure chamber 4 at least partly. A secondside 9 of the wall 7, facing away from the working pressure chamber 4,bounds the product chamber 3 at least partly. The bellows Bg furthercomprises a disc S which, on a side 38 facing the working pressurechamber 4, partly bounds the working pressure chamber 4 and on a side 39facing the product chamber 3 partly bounds the product chamber 3. In theexemplary embodiment shown in FIG. 2, the disc S has a shape virtuallyconforming to an inner wall 40 situated near the first end 12 of thepressure package. The disc S is represented as not being contiguous tothe inner wall 15 of the pressure package. However, it is possible forthe disc S to abut this inner wall 15. In other words, instead of aballoon B, a bellows Bg is included in the pressure package. The otherfeatures and the operation of this pressure package system are equal tothose as described in the description of the embodiment shown in FIG. 1.

FIG. 3 shows a schematic cross section of a third embodiment of apressure package according to the invention. In this case, the pressurepackage system also has a pressure controller 5 and high-pressurechamber 6. However in contrast with the embodiments discussed above, thesecond side 9 of the wall 7 bounds the product chamber 3 virtuallycompletely. The working pressure chamber 4 is partly bounded by theinner walls 15 of the pressure package 2. In this example, too, the wall7 is of flexible design. The first side 8 of the wall bounds the workingpressure chamber 4 at least partly. In this example, product chamber 3comprises a bag Z with an opening 28. Opening 28 links up with theprovision 10 provided in the pressure package for opening the pressurepackage 2.

The operation of the pressure package system 1 shown in FIG. 3 isfurther equal to that of the embodiments shown in FIGS. 1 and 2. Whenthe pressure in the product chamber 3 has decreased in that a user hasallowed fluid to flow from product chamber 3, then, with the aid of thepressure controller 5, propellant will flow from the high-pressurechamber 6 to the working pressure chamber 4. The volume of the workingpressure chamber 4 will thereby increase, and the flexible wall 7, or atleast a part thereof, will move in the direction of the provision foropening the pressure package 2. When in the working pressure chamber 4the working pressure prevails, the working pressure will also prevail inthe product chamber 3. Here, at least a part of the wall 7 may haveassumed a new position and shape, as is represented with the aid of thebroken lines. Preferably, the bag is manufactured from a material havinga low coefficient of friction. The operation is further equal to that ofembodiments shown in FIGS. 1 and 2.

FIG. 4 shows a schematic cross section of a fourth embodiment of apressure package system according to the invention. In this case, theproduct chamber 3 comprises a bellows Bg with an opening 28. In thiscase, too, the opening 28 links up with the provision 10 provided in thepressure package 2 for opening the pressure package 2. In this case too,the wall 7 is of flexible design. While the amount of propellant in theworking pressure chamber 4 is allowed to increase via the pressurecontroller 5, the flexible wall 7 will fold up further. In other words,the wall 7 will be compressed in the manner of an accordion. A wall 29bounding the working pressure chamber 4 at least partly and bounding theproduct chamber 3 at least partly can be of relatively stiff design inthis case. This wall may correspond to the disc S such as it is shown inFIG. 2. The other features and the operation of this variant of thepressure package system according to the invention are equal to thosesuch as they have already been indicated hereinabove in the discussionof the embodiments shown in FIGS. 1-3.

In use, as stated, a propellant will be contained in the high-pressurechamber 6. Preferably, this propellant comprises a relatively inert gas.Thus, the relatively inert gas can comprise, for instance, a gas fromthe group consisting of nitrogen and carbon dioxide.

In the embodiments shown, the outer wall of the pressure package mergesseamlessly with the outer wall of the high-pressure chamber. In otherwords, one continuous outer wall is involved here.

It is possible for the system to be made of two-part design. The firstpart can then comprise the pressure package and the second part can thencomprise the pressure controller with the high-pressure chamber. Asstated and shown in the exemplary embodiments, the first part and thesecond part can be integrally connected with each other.

However, the invention is not limited in any way to the exemplaryembodiments shown. Thus, it is possible for the first and the secondpart to be designed as loose items and to be connectable with each otherfor use. Optionally, the first and second parts are detachablyconnectable with each other. This makes it possible for the first partand the second part to be mechanically connected with each other, forinstance with the aid of a snap connection or a threaded connection,such that the pressure controller 5 aligns with the inlet opening 13 ofthe working pressure chamber 4.

Preferably, in use, the pressure controller is fixed with respect to thepressure package. In all examples, the pressure controller is shown asbeing fixed with respect to an inner wall of the high-pressure chamber.However, what is not excluded is that the pressure controller isincorporated in the pressure package so as to be movable. Although inthe embodiments shown the pressure package is made of substantiallycylinder-shaped design, it is very well possible for the pressurepackage to be designed in other shapes. Thus, a pressure package ofbox-like design may be advantageous.

Although the pressure package can be manufactured substantially frommetal, it is very well possible for the pressure package to bemanufactured substantially from plastic material. This is because theworking pressure can be relatively low, since the working pressure onthe fluid contained in the product chamber 3 can be kept constant. Thisis a major advantage over known systems where the volume of the productchamber 3 remains constant during the use of the fluid contained in theproduct chamber 3. In these known systems, in the initial phase, whenhardly any fluid has been taken from the product chamber 3 yet, theworking pressure must be very high. This is because in these knownsystems, it is to be ensured that still sufficient working pressure willbe exerted on the remainder of fluid still present in an almost emptyproduct chamber 3 after the fluid has been used up almost completely.

It will be clear that the provision 10 for opening the pressure packagecan comprise many types of openings. To be considered here are, forinstance, a screw cap, a stopper, slide, etc. Thus, it will also beclear that the wall 7 in some embodiments can be made of both flexibleand elastic design.

It is further noted that the pressure controller may also be designeddifferently than the pressure controller shown. Also eligible for useare pressure controllers where the reference pressure is obtained with aspring instead of with a gas. Thus, instead of a plunger, a membrane forinstance provided with a stem can be used in the pressure controller.All such variants are understood to fall within the invention.

1. A pressure package system for pressurizing a fluid to be delivered,the system comprising: a pressure package comprising: a product chamberfor holding the fluid, and a working pressure chamber for holding apropellant at a substantially constant working pressure, the workingpressure chamber having an opening, a high-pressure chamber configuredto hold the propellant in supply at a pressure higher than the workingpressure, a pressure controller in a fluid connection between theworking pressure chamber and the high-pressure chamber, the pressurecontroller being disposed within the high-pressure chamber andcomprising a reference pressure chamber confining a gas at a referencepressure, a cylinder in the high-pressure chamber having first andsecond open ends, the first open end connecting to the opening of theworking pressure chamber, and the second open end being closed off bythe pressure controller, and a flexible wall, at least a portion of afirst side of the flexible wall bounding at least a portion of theworking pressure chamber and a second side of the flexible wall facingaway from the working pressure chamber, at least a portion of the secondside of the wall bounding at least a portion of the product chamber,wherein, the pressure controller is configured to supply the propellantfrom the high-pressure chamber to the working pressure chamber to keepthe working pressure in the working pressure chamber substantiallyconstant and the supply of the propellant to the working pressurechamber is determined based on the reference pressure.
 2. A pressurepackage system according to claim 1, characterized in that the pressurepackage comprises a provision for opening the pressure package for thepurpose of allowing fluid operatively contained in the product chamberto flow out of the product chamber.
 3. A pressure package systemaccording to claim 1, characterized in that the first side of the wallbounds the working pressure chamber at least substantially completely.4. A pressure package system according to claim 3, characterized in thatthe product chamber is further bounded at least partly by the pressurepackage.
 5. A pressure package system according to claim 1,characterized in that the working pressure chamber comprises an innerspace of a balloon in which, in use, the propellant can be received. 6.A pressure package system according to claim 1, characterized in thatthe working pressure chamber comprises an inner space of a bellows inwhich, in use, the propellant can be received.
 7. A pressure packagesystem according to claim 1, characterized in that the second side ofthe wall bounds the product chamber at least substantially completely.8. A pressure package system according to claim 1, characterized in thatthe working pressure chamber is further at least partly bounded by innerwalls of the pressure package.
 9. A pressure package system according toclaim 1, characterized in that the product chamber comprises a bag withan opening, the opening linking up with the provision arranged in thepressure package for opening the pressure package.
 10. A pressurepackage system according to claim 9, characterized in that the bag ismanufactured from a material having a low coefficient of friction.
 11. Apressure package system according to claim 1, characterized in that theproduct chamber comprises a bellows with an opening, the opening linkingup with the provision arranged in the pressure package for opening thepressure package.
 12. A pressure package system according to claim 1,characterized in that propellant is included in the high pressurechamber.
 13. A pressure package system according to claim 12,characterized in that the propellant comprises a relatively inert gas.14. A pressure package system according to claim 13, characterized inthat the relatively inert gas comprises a gas from the group consistingof nitrogen and carbon dioxide.
 15. A pressure package system accordingto claim 1, characterized in that the system is of two-part design, witha first part comprising the pressure package and a second partcomprising the pressure controller with the high-pressure chamber.
 16. Apressure package system according to claim 15, characterized in that thefirst part and the second part are integrally connected with each other.17. A pressure package system according to claim 15, characterized inthat the first part and the second part are designed as loose items andare connectable with each other for use.
 18. A pressure package systemaccording to claim 1, characterized in that in use the pressurecontroller is fixed with respect to the pressure package.
 19. A pressurepackage system according to claim 1, characterized in that the pressurepackage is substantially cylinder-shaped, the pressure package beingprovided with a first end and a second end, the pressure package beingfurther provided with an inlet opening for the propellant situatedadjacent the first end and wherein the provision for opening thepressure package is situated adjacent the second end.
 20. A pressurepackage system according to claim 5, characterized in that the balloonis designed such that the balloon, while being filled with thepropellant, stretches substantially in an axial direction of thepressure package.
 21. A pressure package system according to claim 6,characterized in that the bellows is so designed that the bellows, whenbeing filled with propellant, expands substantially in an axialdirection of the pressure package.
 22. A pressure package systemaccording to claim 1, characterized in that the pressure package is madeof box-like design.
 23. A pressure package system according to claim 1,characterized in that the pressure package is manufactured substantiallyfrom a plastic material.
 24. A pressure package system according toclaim 1, characterized in that the pressure controller is fixed withrespect to an inner wall of the high-pressure chamber.
 25. An articlefor pressurizing a fluid to be delivered, comprising: a product chamberconfigured to hold the fluid, a working propellant chamber having anexpandable wall in contact with the fluid and configured to hold apropellant at a working pressure, at least a portion of a first side ofthe expandable wall bounding at least a portion of the workingpropellant chamber, at least a portion of a second side of theexpandable wall, facing away from the working propellant chamber,bounding at least a portion of the product chamber such that the fluidis separated from the propellant, and the working propellant chamberhaving an opening, a reservoir propellant chamber configured to hold thepropellant at a pressure higher than the working pressure, a pressurecontroller in a fluid connection between the working propellant chamberand the reservoir propellant chamber, the pressure controller beingdisposed within the reservoir propellant chamber and comprising areference pressure chamber confining a gas at a reference pressure, thereference pressure determining the working pressure in the workingpropellant chamber, and a cylinder in the reservoir propellant chamberhaving first and second open ends, the first open end connecting to theopening of the working propellant chamber, and the second open end beingclosed off by the pressure controller; wherein, expansion of theexpandable wall applies pressure to the fluid held within the productchamber and, upon release of fluid from the product chamber, theexpandable wall of the working propellant chamber is configured toexpand against the remaining fluid and the pressure controller isconfigured to deliver propellant from the reservoir propellant chamberto the working propellant chamber to keep the working pressure withinthe working propellant chamber substantially constant.
 26. The articleof claim 25, wherein the expandable wall is elastic.
 27. The article ofclaim 25, wherein the expandable wall comprises a bellows.
 28. Anarticle for pressurizing a fluid to be delivered, comprising: a productchamber comprising a fluid to be delivered, a working propellant chamberhaving an expandable wall in contact with the fluid and comprising apropellant at a working pressure, at least a portion of a first side ofthe expandable wall bounding at least a portion of the workingpropellant chamber, at least a portion of a second side of theexpandable wall, facing away from the working propellant chamber,bounding at least a portion of the product chamber such that the fluidis separated from the propellant, and the working propellant chamberhaving an opening, a reservoir propellant chamber comprising thepropellant at a pressure higher than the working pressure, a pressurecontroller in a fluid connection between the working propellant chamberand the reservoir propellant chamber, the pressure controller beingdisposed within the reservoir propellant chamber and comprising areference pressure chamber confining a gas at a reference pressure, thereference pressure determining the working pressure in the workingpropellant chamber, and a cylinder in the reservoir propellant chamberhaving first and second open ends, the first open end connecting to theopening of the working propellant chamber, and the second open end beingclosed off by the pressure controller; wherein, expansion of theexpandable wall applies pressure to the fluid held within the productchamber and, upon release of fluid from the product chamber, theexpandable wall of the working propellant chamber expands against theremaining fluid and the pressure controller delivers propellant from thereservoir propellant chamber to the working propellant chamber to keepthe working pressure within the working propellant chamber substantiallyconstant.